The effects of various immunosuppressive agents on lymphocyte functions are being studied to identify their sites and mechanisms of action. Various agents, such as corticosteroids, cyclophosphamide, and azathioprine, are also being used as tools to study cell-mediated immune regulation in normal lymphocytes, as well as those from patients with autoimmune disorders, particularly SLE. The major goals of these studies are to further eludicate the mechanisms of altered immunoregulation, as well as to find new parameters of immune function to measure and/or monitor responses of patients receiving pharmacologic immunosuppression.